This SBIR program intends to develop a group of new technologies for the large scale and inexpensive production of bio-labels based on gold nanocrystals (GoldTagsTM). Gold nanocrystals, usually known as colloidal gold, have been widely explored for bio-labeling for many years and are the only type of nanocrystaMabels making a visible impact in daily life for modem society-pregnancy test kits based on gold nanocrystals available in supermarkets. In comparison to semiconductor nanocrystals labels, gold ones are nontoxic, environmentally benign, and exhibit high extinction coefficients-bright for colormetric applications. However, the production of high quality gold nanocrystals on a large scale has been a bottle-neck. The current art-in-state technologies to produce Au nanocrystals are low productivity, high cost, difficult to make relatively small size nanocrystals, poor size range and size distribution, and difficult to make them biocompatible. The patent-pending technology has a high yield of high quality gold nanocrystals, about 1000 times in comparison to the standard citrate-reduction method. Substantially better than the Brust method, the size range, size distribution, and the surface accessibility of the nanocrystals from this unique method are all excellent. This project will also solve another key challenge for Au nanocrystals as bio-labels by a new scheme-dendron-nanocrystals and box-nanocrystals-jointly invented by NN-Labs and our subcontractor. The overall technical objective of this SBIR program is to extend a successful laboratory synthetic method for high quality gold nanocrystals to commercial scale and convert these high quality nanocrystals to bio-ready GoldTagTM. [unreadable] [unreadable]